The Alpha Male of a species quickly establishes his dominance of a territory and lets the rest of the pack know that he is not to be messed with. Enter the 2006 Hummer H1 Alpha, a performance-enhanced version of the original H1, itself based on the tank-like HUMVEE used by the U.S. military. Enhanced performance comes not in a blue pill, but care of a larger 6.6-liter Duramax diesel V8, which adds nearly 100-hp to its output, and a new 5-speed automatic transmission with a tow/haul mode.

Other additions available in the H1 Alpha include bigger brakes and increased ground clearance, along with more stylish 17-inch alloy wheels. With limited slip differentials and optional locking differentials, the Alpha means business when it comes to off-roading. Except for some surface badging, the Alpha differs little from the regular H1, which is only offered in Alpha form for 2006. It is offered as a 4WD, four-seater wagon or open-top, with a 58 cubic foot cargo area. Leather seats, a 6-CD player, and full power features bring it a notch above standard issue military vehicle.

The new Duramax engine is a noticeable step up in terms of both hauling power and off-road performance, for which the H1 Alpha is best suited. Highway driving suffers in acceleration and unwieldy maneuverability, and the gas mileage is expectedly pitiful. Hummer does brag you can go about 500 miles without filling up a tank, but of course its dual tanks hold about 51 gallons (that's around $150 for a fill-up at current gas prices). The oversized vehicle is best suited for those doing serious all-terrain driving or who just want a status symbol, though that title is quickly being surpassed by the smaller H2 and H3.